A300 flight crew reported they mistakenly took the clearance meant for a company aircraft with a sim...

Attributes
ACN	1519552
Time
Date	201802
Local Time Of Day	1201-1800
Place
Locale Reference	ZME.ARTCC
State Reference	TN
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A300
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

While level at 33;000 feet; we heard what sounded like a clearance for us; flight abc; to climb to 34;000 feet; our final altitude. I read the clearance back and the pilot flying set the altitude and began to climb. As soon as we began our climb flight abd asked center if the clearance was for them because they had not responded. The controller immediately said; 'flight abc descend immediately to FL330 for traffic.' at this point; we were at 33;330 feet (the highest altitude we had climbed to) and descending back to 33;000 feet. We were alerted to traffic 15 miles away at 34;000 feet. There was no traffic RA; nor was there any further compromise of the safety of flight. This was a misunderstanding of ATC instructions. We without a doubt thought that the clearance was for us; flight abc. I read it back and we were never corrected before acting on the supposed climb to a flight level that happened to also be our final cruise altitude. We were also unaware that flight abd was on the frequency until they questioned the clearance. Mitigate having similar sounding call signs in the same airspace at the same time.

Original NASA ASRS Text

Title: A300 flight crew reported they mistakenly took the clearance meant for a company aircraft with a similar sounding call sign.

Narrative: While level at 33;000 feet; we heard what sounded like a clearance for us; Flight ABC; to climb to 34;000 feet; our final altitude. I read the clearance back and the Pilot Flying set the altitude and began to climb. As soon as we began our climb Flight ABD asked center if the clearance was for them because they had not responded. The controller immediately said; 'Flight ABC DESCEND IMMEDIATELY TO FL330 FOR TRAFFIC.' At this point; we were at 33;330 feet (the highest altitude we had climbed to) and descending back to 33;000 feet. We were alerted to traffic 15 miles away at 34;000 feet. There was no traffic RA; nor was there any further compromise of the safety of flight. This was a misunderstanding of ATC instructions. We without a doubt thought that the clearance was for us; Flight ABC. I read it back and we were never corrected before acting on the supposed climb to a flight level that happened to also be our final cruise altitude. We were also unaware that Flight ABD was on the frequency until they questioned the clearance. Mitigate having similar sounding call signs in the same airspace at the same time.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.